Ceramic article with enhanced structural and thermal stability and method of making same

ABSTRACT

A ceramic spinner and a method of making the same is provided. The ceramic spinner includes: a top portion with a first opening, the first opening having a first diameter; a base portion with a second opening, the second opening having a second diameter smaller than the first diameter; a cylindrical portion extending between the top portion and the base portion, the cylindrical portion including a peripheral outer wall, a peripheral inner wall, and a plurality of through holes extending between the peripheral outer wall and the peripheral inner wall. The cylindrical portion may include a material having a module of rupture (MOR) exceeding 100 MPa, a Mohs hardness exceeding 8, or a Young&#39;s Modulus exceeding 250 GPa, or any combinations thereof.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the filing date of U.S.provisional application No. 63/279,278 filed on Nov. 15, 2021, which isincorporated by reference in its entirely herein.

FIELD

The disclosure relates generally to a ceramic article and a method ofmaking the same, and more particularly, embodiments of the disclosurerelate to a ceramic article with enhanced structural and thermalstability for glass wool production and a method of making the same.

BACKGROUND

Glass wool is typically produced from a sand, limestone, soda ash, andrecycled glass. In a typical process, these constituents are crushed andmixed, before being melted and refined together at high temperatures,for example, temperatures in excess of 2650° F. The resulting moltenmaterial (or “molten glass”) is then gravity fed into a rotary cylinderor a spinning bowl, known as a “spinner” or “fiberizer.” The spinnertypically has a large array of small through holes. As the spinner israpidly rotated, the centrifugal forces pulls the molten material towardthe outer wall of the spinner and through the array of the small throughholes of the spinner to continuously cast thin strands. For use as fiberglass wool, an ultralight insulative material used for applications suchas housing and aerospace, the strands are mixed with resins and curedinto the final product.

BRIEF DESCRIPTION

All aspects, examples and features mentioned below can be combined inany technically possible way.

An aspect of the disclosure provides a ceramic article comprising: a topportion with a first opening, the first opening having a first diameter;a base portion with a second opening, the second opening having a seconddiameter smaller than the first diameter; a cylindrical portionextending between the top portion and the base portion, the cylindricalportion including a peripheral outer wall, a peripheral inner wall, anda plurality of through holes extending between the peripheral outer walland the peripheral inner wall, wherein the cylindrical portion comprisesa material having a module of rupture (MOR) exceeding 100 Megapascals(MPa), a Mohs hardness exceeding 8, or a Young's Modulus exceeding 250Gigapascals (GPa), or any combinations thereof.

Another aspect of the disclosure includes the preceding aspect, andwherein the cylindrical portion includes a first region adjacent andsurrounding each of the plurality of through holes and a second regionadjacent the first region, wherein the material in the first region hasa first characteristics, and the material in the second region includesa second characteristics that is different than the firstcharacteristics.

Another aspect of the disclosure includes any of the preceding aspects,and the material in the first region has a higher density than that ofthe material in the second region, thereby providing a higher-densityinner surface surrounding each of the plurality of through holes.

Another aspect of the disclosure includes any of the preceding aspects,and wherein the higher-density inner surface has an average width ofabout 50 micrometers (μm).

Another aspect of the disclosure includes any of the preceding aspects,and wherein the material has a thermal conductivity in a range of 15-75Watts per meter per degree Celsius, or a thermal expansion in a range of3-6 micrometer per meter per degree Celsius, or both.

Another aspect of the disclosure includes any of the preceding aspects,and wherein the cylindrical portion extends radially between the topportion and the base portion, and the base portion includes a laterallyextending base portion and a sloped base portion coupling the laterallyextending base portion to the radially extending cylindrical portion.

Another aspect of the disclosure includes any of the preceding aspects,and wherein the plurality of through holes has an average inner diameterrange from about 250 μm to about 2.5 millimeter (mm).

Another aspect of the disclosure includes any of the preceding aspects,and wherein the material comprises a nitride bonded silicon carbidematerial.

Another aspect of the disclosure includes any of the preceding aspects,and wherein the ceramic article is a glass wool spinner.

An aspect of the disclosure provides a method for preparing an articlefrom a cast ceramic workpiece, the method comprising: sintering the castceramic workpiece to form a sintered ceramic body, the sintered ceramicbody including: a top portion with a first opening, the first openinghaving a first diameter; a base portion with a second opening, thesecond opening having a second diameter smaller than the first diameter;and a cylindrical portion extending between the top portion and the baseportion, the cylindrical portion including a peripheral outer wall and aperipheral inner wall, and forming a plurality of through holesextending between the peripheral outer wall and the peripheral innerwall of the cylindrical portion, wherein the cylindrical portioncomprises a material having a module of rupture (MOR) exceeding 100Megapascals (MPa), a Mohs hardness exceeding 8, or a Young's Modulusexceeding 250 Gigapascals (GPa), or any combinations thereof.

Another aspect of the disclosure includes the preceding method, and theforming further comprises: determining a region of interests (ROI) inthe sintered ceramic body for forming the plurality of through holes;directing an energy source to the ROI; and forming the plurality ofthrough holes within the ROI, each of the plurality of through holesextending between the peripheral outer wall and the peripheral innerwall of the cylindrical portion of the sintered ceramic body.

Another aspect of the disclosure includes any of the preceding methods,and wherein the energy source is an ultrasound energy.

Another aspect of the disclosure includes any of the preceding methods,and wherein the energy source is a laser.

Another aspect of the disclosure includes any of the preceding methods,further comprising: liquifying and vaporizing the material within theROI in forming the plurality of through holes within the ROI;liquifying, without vaporizing, the material surrounding each of theplurality of through holes and forming a first region adjacent andsurrounding each of the plurality of through holes; and allowing thematerial in the first region to resolidify, wherein the material in thefirst region has a first characteristics, and the material in a secondregion adjacent the first region has a second characteristics that isdifferent than the first characteristics.

Another aspect of the disclosure includes any of the preceding methods,and further comprising: forming a higher-density inner surface of thefirst region, wherein the higher-density inner surface extends laterallythrough both the peripheral outer wall and the peripheral inner wall.

Another aspect of the disclosure includes any of the preceding methods,and wherein the material in the first region has a higher materialdensity than that of the second region of the cylindrical portion.

Another aspect of the disclosure includes any of the preceding methods,and wherein the higher-density inner surface has an average width ofabout 50 μm.

Another aspect of the disclosure includes any of the preceding methods,and wherein the material has a thermal conductivity in a range of 15-75Watts per meter per degree Celsius.

Another aspect of the disclosure includes any of the preceding methods,and wherein the material has a thermal expansion in a range of 3-6micrometer per meter per degree Celsius.

Another aspect of the disclosure includes any of the preceding methods,and wherein the plurality of through holes has an average inner diameterin a range of about 250 μm to about 2.5 mm.

Another aspect of the disclosure includes any of the preceding methods,and wherein the material comprises a nitride bonded silicon carbidematerial.

Another aspect of the disclosure includes any of the preceding methods,and wherein the article is a glass wool spinner.

Another aspect of the disclosure includes any of the preceding methods,and wherein the cast ceramic workpiece is a singular cast ceramicworkpiece.

An aspect of the disclosure provides a ceramic spinner comprising: a topportion with a first opening, the first opening having a first diameter;a base portion with a second opening, the second opening having a seconddiameter smaller than the first diameter; a cylindrical portionextending between the top portion and the base portion, the cylindricalportion including a peripheral outer wall, a peripheral inner wall, anda plurality of through holes extending between the peripheral outer walland the peripheral inner wall, wherein the cylindrical portion furtherincludes a first region surrounding each of the plurality of holes and asecond region adjacent the first region, and wherein a material in thefirst region has a first characteristics, and a material in the secondregion has a second characteristics that is different than the firstcharacteristics.

Another aspect of the disclosure includes any of the preceding aspects,and wherein the cylindrical portion includes a material having a moduleof rupture (MOR) exceeding 100 MPa, a Mohs hardness exceeding 8, or aYoung's Modulus exceeding 250 GPa, or any combinations thereof.

Another aspect of the disclosure includes any of the preceding aspects,and wherein the material having the first characteristics has a higherdensity than that of the material having the second characteristics,thereby providing a higher-density inner surface surrounding each of theplurality of holes.

Another aspect of the disclosure includes any of the preceding aspects,wherein the higher-density inner surface has an average width of about50 μm.

Another aspect of the disclosure includes any of the preceding aspects,and wherein the material has a thermal conductivity in a range of 15-75Watts per meter per degree Celsius.

Another aspect of the disclosure includes any of the preceding aspects,and wherein the material has a thermal expansion in a range of 3-6micrometer per meter per degree Celsius.

Another aspect of the disclosure includes any of the preceding aspects,and wherein each of the plurality of holes has an average inner diameterin a range of about 250 μm to about 2.5 mm.

Another aspect of the disclosure includes any of the preceding aspects,and wherein the material comprises a nitride bonded silicon carbide.

Another aspect of the disclosure includes any of the preceding aspects,and where the ceramic spinner is a glass wool spinner.

Another aspect of the disclosure includes any of the preceding aspects,and wherein the cast ceramic workpiece is a singular cast ceramicworkpiece.

Two or more aspects described in this disclosure, including thosedescribed in this summary section, may be combined to formimplementations not specifically described herein.

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features, objectsand advantages will be apparent from the description and drawings, andfrom the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this disclosure will be more readilyunderstood from the following detailed description of the variousaspects of the disclosure taken in conjunction with the accompanyingdrawings that depict various embodiments of the disclosure, in which:

FIG. 1 is a flow diagram of a rotary spin process using a ceramicspinner, according to embodiments of the current disclosure.

FIG. 2A is a perspective view of a ceramic spinner, according toembodiments of the current disclosure; FIG. 2B is a top view of theceramic spinner of FIG. 2A, according to embodiments of the disclosure;FIG. 2C is a cross sectional view of the ceramic spinner along the lineK-K of FIG. 2B, according to embodiments of the disclosure.

FIG. 3 is a flow chart of a method of preparing an article from a castceramic workpiece, according to embodiments of the current disclosure.

FIG. 4 is a flow chart illustrating additional method steps in preparingan article from a cast ceramic workpiece, according to embodiments ofthe current disclosure.

FIG. 5 illustrates a rotary ultrasonic drilling process for drillingholes in a ceramic workpiece, according to embodiments of the currentdisclosure.

FIG. 6 is a cross-sectional view of a portion of a ceramic article wherea plurality of through holes are made via a laser drilling, according toembodiments of the current disclosure.

FIG. 7 is a magnified cross-sectional view of a portion of the ceramicarticle of FIG. 6 , showing a through hole and surrounding structuraldetails.

FIG. 8A shows a perspective view of another embodiment of ceramicspinner, according to embodiments of the current disclosure; FIG. 8B isa top view of the ceramic spinner of FIG. 8A, according to embodimentsof the disclosure; FIG. 8C is a cross sectional view of the ceramicspinner along the line A-A of FIG. 8B, according to embodiments of thedisclosure.

FIG. 9 illustrates a result of a finite element analysis (FEA) thatdetermines the stresses imparted on the ceramic article of FIG. 8A bythe rotational forces, according to embodiments of the currentdisclosure.

FIG. 10 shows more details of the finite element analysis (FEA) resultsof a cross sectional view of a portion of the ceramic article takenalong the line S-S of FIG. 9 , according to embodiments of the currentdisclosure.

FIGS. 11A and 11B compare measurements of stress (σ) vs strain (ε)curves of a reference titanium alloy metal material (FIG. 11A) and asilicon carbide material (FIG. 11B) of the instant disclosure, accordingto embodiments of the current disclosure.

FIG. 12 compares parameters for rigidity (Youngs Modulus, GPa) andhardness (MOH) of various materials for a spinner, according toembodiments of the current disclosure.

FIG. 13 shows a temperature load over time profile of a thermal shocktest, according to embodiments of the current disclosure.

FIG. 14 shows comparison of mechanical strength (MPa) and density(lb/in³) profile of various materials for a spinner, according toembodiments of the current disclosure.

FIG. 15 provides a comparison of thermal expansion and thermalconductivity of various materials for a spinner, according toembodiments of the current disclosure.

FIG. 16 summarizes a comparison of the material specifications matrixbetween the materials of the current disclosure and certain referencemetals, according to embodiments of the current disclosure.

It is noted that the drawings of the disclosure are not necessarily toscale. The drawings are intended to depict only typical aspects of thedisclosure and therefore should not be considered as limiting the scopeof the disclosure. In the drawings, like numbering represents likeelements between the drawings.

The foregoing drawings show some of the processing associated accordingto several embodiments of this disclosure. In this regard, each drawingor block within a flow diagram of the drawings represents a processassociated with embodiments of the method described. It should also benoted that in some alternative implementations, the acts noted in thedrawings or blocks may occur out of the order noted in the figure or,for example, may in fact be executed substantially concurrently or inthe reverse order, depending upon the act involved. Also, one ofordinary skill in the art will recognize that additional blocks thatdescribe the processing may be added.

DETAILED DESCRIPTION

Certain embodiments will now be described to provide an overallunderstanding of the principles of the structure, function, manufacture,and use of the methods, systems, and devices disclosed herein. One ormore examples of these embodiments are illustrated in accompanyingdrawings. Those skilled in the art will understand that methods,systems, and devices specifically described herein and illustrated inthe accompanying drawings are non-limiting embodiments. Featuresillustrated or described in connection with one embodiment may becombined with features of other embodiments. Such modifications andvariations are intended to be included within the scope of the presentdisclosure.

As an initial matter, in order to clearly describe the subject matter ofthe current disclosure, it will become necessary to select certainterminology when referring to and describing relevant machinecomponents. To the extent possible, common industry terminology will beused and employed in a manner consistent with its accepted meaning.Unless otherwise stated, such terminology should be given a broadinterpretation consistent with the context of the present applicationand the scope of the appended claims. Those of ordinary skill in the artwill appreciate that often a particular component may be referred tousing several different or overlapping terms. What may be describedherein as being a single part may include and be referenced in anothercontext as consisting of multiple components. Alternatively, what may bedescribed herein as including multiple components may be referred toelsewhere as a single part.

It is often required to describe parts that are disposed at differingradial positions with regard to a center axis. The term “radial” refersto movement or position perpendicular to an axis. For example, if afirst component resides closer to the axis than a second component, itwill be stated herein that the first component is “radially inward” or“inboard” of the second component. If, on the other hand, the firstcomponent resides further from the axis than the second component, itmay be stated herein that the first component is “radially outward” or“outboard” of the second component. The term “axial” refers to movementor position parallel to an axis. Finally, the term “circumferential”refers to movement or position around an axis. It will be appreciatedthat such terms may be applied in relation to the center axis of theturbine.

In addition, several descriptive terms may be used regularly herein, asdescribed below. The terms “first”, “second”, and “third” may be usedinterchangeably to distinguish one component from another and are notintended to signify location or importance of the individual components.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components but do not preclude the presence or addition of one ormore other features, integers, steps, operations, elements, components,and/or groups thereof. “Optional” or “optionally” means that thesubsequently described event or circumstance may or may not occur orthat the subsequently describe component or element may or may not bepresent, and that the description includes instances where the eventoccurs or the component is present and instances where it does not or isnot present.

Where an element or layer is referred to as being “on,” “engaged to,”“connected to” or “coupled to” another element or layer, it may bedirectly on, engaged to, connected to, or coupled to the other elementor layer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto,” “directly connected to” or “directly coupled to” another element orlayer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

The current disclosure provides a ceramic article and method of makingthe same. In particular, embodiments of the disclosure relate to aceramic article with enhanced structural and thermal stability for fiberglass wool production and method of making the same.

Traditionally, metallic spinners have been used in producing glass wool,with a range of alloys used over the years, for example, structurallyhard alloys with high operating temperatures. The spinners typicallyhave a very large number of miniscule holes (e.g., 40,000+ holes atabout 0.016″, i.e., about 400 micrometers (μm) in diameter for eachhole). At the startup of production, each hole is its smallest and bestsized to produce the highest quality glass wool. As the hot and viscousmolten glass passes through the holes it mechanically erodes themthrough friction and fatigue, increasing the inner dimension of theholes, and by relation, the outer dimension of the produced glass wool.This decreases the quality of the glass wool, and typically within only120 hours of service the otherwise functional metal spinner is no longerable to produce quality fiber glass wool, and then the entire processmust be shut down for the metallic spinner to be replaced and preheatedfor startup.

Therefore, the market is still in need for a spinner with highstructural and thermal stability at high temperatures, suitable for usein a rotary spin process in producing high quality glass wool product.

The current disclosure solves the issues faced by the conventional metalspinners by providing a ceramic spinner or article including a pluralityof through holes and method of making the same, where the ceramicspinner has high mechanical stability at high temperatures and enhancederosion resistance. More specifically, the solution developed in thecurrent disclosure utilizes a combination of ceramics materials withspecific parameters and unique machining methods to generate a ceramicarticle suitable for use in applications including, but not limited to,a rotary spin process in producing high quality glass wool products.

As will be discussed later, various factors need to be considered indesigning a non-metal spinner. Furthermore, complex interplay betweendesign parameters/factors adds to the challenges in material selection.The field has consistently overlooked and/or dismissed the possibilityof using a refractory ceramic to replace the metal. Likely the yieldstrength and brittleness of refractory ceramic such as fused silica oralumina often disqualify these materials. Furthermore, the manufacturinglimitations of ceramic materials, especially the hardest ones,traditionally led the industry away from the ceramic materials andtoward favoring softer, and more machinable metals.

Method of manufacturing ceramic spinners posts additional challenges.For example, no commercial method exists to date to form a functionalspinner from a singular cast ceramic workpiece including silicon carbidematerial. One of the manufacturing challenges is to produce an array oftiny through holes throughout a thin-walled body of the ceramicworkpiece. The current disclosure combines the benefits of data-guideddesign of mechanical properties of a ceramic workpiece with theprecision of specialized processing, such as a precision laser drilling,to manufacture each individual through hole in its exact location alongthe ceramic workpiece, and provides a spinner that meets the designspecification suitable for producing high quality glass wool products.

FIG. 1 illustrates a rotary spin process in processing a molten glass,using a ceramic spinner of the instant disclosure. In the process, amolten glass 100, once formed, is gravity fed into a ceramic spinner110. The centrifugal forces produced by the rapidly spinning spinner 110pulls the molten material 100 toward the outer wall of the spinner 110and through an array of tiny, precisely manufactured through holes 120to continuously cast thin strands of fiber glass 130, typically rangingfrom 3 to 25 μm in diameter. An outside stream of high velocity, hot airthen stretches the strands 130, and a separate stream of highlyturbulent cold air 140 hardens them to the point of breakage(attenuation). At the same time, a binder spray 150 is applied to bondthe fibers 130 together, with a typical binder solution includingphenol-formaldehyde resin, water, urea, lignin, silane, and ammonia, aswell as coloring agents. The formed glass fibers 130 are thentransported by a conveyor 160 to a curing oven 180 for further treatmentwhile forming exhaust 170 is pulled through conveyor 160.

FIG. 2A shows a perspective view of a ceramic article 200, for example,a ceramic spinner, according to embodiments of the current disclosure;FIG. 2B is a top view of the ceramic article of FIG. 2A; and FIG. 2C isa cross sectional view of the ceramic article along the line K-K of FIG.2B, according to embodiments of the disclosure. As illustrated in FIG.2A, the ceramic article 200 may include: a top portion 210 with a firstopening 212, the first opening 212 having a first diameter D₁ (FIG. 2C);a base portion 214 with a second opening 216 having a second diameter D₂smaller than the first diameter D₁ (FIG. 2C); and a cylindrical portion218 extending between the top portion 210 and the base portion 214, thecylindrical portion 218 having a peripheral outer wall 220, a peripheralinner wall 222, and a plurality of through holes 224 extending betweenthe peripheral outer wall 220 and the peripheral inner wall 222. Inembodiments, top portion 210 extends laterally (e.g., direction “L” inFIG. 2A). In embodiments, cylindrical portion 218 extends radiallybetween top portion 210 and base portion 214 (e.g., direction “R” inFIG. 2A). In embodiments, cylindrical portion 218 has a thin wallthickness T defined by the peripheral outer wall 220 and the peripheralinner wall 222. In embodiments, D₁ may be in a range of about 200-400mm, or about 300-350 mm, or about 300-320 mm. D₂ may be in a range ofabout 50-300 mm, or in a range of about 100-250 mm, or in a range ofabout 130-210 mm. T may be in a range of 1-20 mm, or in a range of 5-15mm, or about 7-11 mm. It is to be understood that dimensions of D₁, D₂and T are provided as non-limiting examples, and that the embodiments ofthe current disclosure are not limited to the disclosed dimensions.Various dimensions of the ceramic article are intended to be includedwithin the scope of the present disclosure. Furthermore, the ceramicarticle may be developed or used for different applications, including,but not limited to, a ceramic spinner for glass wool production.

In certain embodiments, the cylindrical portion 218, including theperipheral outer wall 220 and the peripheral inner wall 222, includes amaterial having a module of rupture (MOR) exceeding 100 Megapascals(MPa), a Mohs hardness exceeding 8, or a Young's Modulus exceeding 250Gigapascals (GPa), or any combinations thereof. In some embodiments, thematerial includes a nitride bonded silicon carbide material. Inembodiments, the material has a thermal conductivity in a range of 15-75Watts per meter per degree Celsius. In some embodiments, the materialhas a thermal expansion in a range of 3-6 micro-meter per meter perdegree Celsius.

In embodiments, the plurality of through holes has an average innerdiameter range from about 250 micrometers (μm) to about 2.5 millimeters(mm).

In some embodiments, the ceramic spinner of FIGS. 2A-2C includes asingular cast ceramic body.

FIG. 3 is a flow chart of a method for preparing a ceramic article,according to embodiments of the disclosure. The method may include:sintering a cast ceramic workpiece to form a sintered ceramic body(S302), and forming a plurality of through holes extending between theperipheral outer wall and the peripheral inner wall of a cylindricalportion of the sintered ceramic body (S304). In embodiments, thesintered ceramic body may include: a top portion with a first opening,the first opening having a first diameter; a base portion with a secondopening, the second opening having a second diameter smaller than thefirst diameter; and a cylindrical portion extending between the topportion and the base portion, the cylindrical portion including aperipheral outer wall and a peripheral inner wall, and forming aplurality of through holes extending between the peripheral outer walland the peripheral inner wall of the cylindrical portion, where theperipheral outer wall and the peripheral inner wall include a materialhaving a module of rupture (MOR) exceeding 100 Megapascals (MPa), a Mohshardness exceeding 8, or a Young's Modulus exceeding 250 Gigapascals(GPa), or any combinations thereof.

In some embodiments, the ceramic article is prepared from a singularcast ceramic workpiece and the sintering step includes sintering asingular cast ceramic workpiece. In embodiments, the ceramic article isprepared from a singular cast ceramic workpiece including a siliconcarbide material. In embodiments, the ceramic article is prepared from asingular cast ceramic workpiece including a nitride bonded siliconcarbide material.

In embodiments, the ceramic article is a glass wool spinner.

In some embodiments, the material has a thermal conductivity in a rangeof 15-75 Watts per meter per degree Celsius. In some embodiments, thematerial has a thermal expansion in a range of 3-6 micro-meter per meterper degree Celsius.

In embodiments, the plurality of through holes has an average innerdiameter range from about 250 micrometers (μm) to about 2.5 millimeters(mm).

FIG. 4 is a flow chart illustrating additional method steps forpreparing a ceramic article. The method may further include: determininga region of interests (ROI) in the sintered ceramic body for forming theplurality of through holes (S402); directing an energy source to the ROIin the sintered ceramic body (S404); and forming the plurality ofthrough holes within the ROI (S406). In embodiments, each of theplurality of through holes extends between the peripheral outer wall andthe peripheral inner wall of the cylindrical portion.

In embodiments, the energy source is an ultrasound energy. Inembodiments, the energy source is a laser.

FIG. 5 illustrates a rotary ultrasonic drilling process for drillingholes in a ceramic workpiece. In embodiments, forming the plurality ofholes could be achieved by a rotary ultrasonic drilling process.Conventional methods of machining a ceramics workpiece uses a rotarydrill bit which grinds material away in order to drill holes on theceramic workpiece, which causes sufficient wear and difficulty. Incontrast, in certain embodiments of the current disclosure, a rotaryultrasonic drilling utilizing an abrasive coolant 502 is used. Theabrasive coolant 502 is sprayed through a core drill 504 in a directionA onto a ceramic workpiece 506, and flows out of core drill 504 in adirection B. Applying vibration and rotation of core drill 504 andconstant force 508 facilitates the drilling to produce a plurality ofholes 510. Compared to the conventional drilling method, the rotaryultrasonic drilling process of the instant disclosure improves brittlefracture mechanism and provides much higher machining rate (6-10 timeshigher than conventional drilling) and more cost-effective results.

FIG. 6 is a cross-sectional view of a portion of a ceramic article wherea plurality of through holes 624 are made via a laser drilling. Thelaser drilling provides another unique method for producing embodimentsof the instant disclosure. Rather than relying on a conventional methodof mechanically abrading and grinding ceramic material away, the laserdrilling utilizes optical amplification to rapidly heat and vaporize theceramic material and to generate a plurality of through holes in theceramic article. This process has shown favorable results, achieving aplurality of straight bores in the ceramic workpiece. As illustrated inFIG. 6 , a region of interests (ROI) 602 is determined in a sinteredceramic body 600 for forming the plurality of through holes. A laserenergy source is then directed to the ROI 602. As the laser energysource is applied to ROI 602, the portion of the ceramic material insidethe ROI 602 along the path of the laser is liquified and vaporized,forming each of the plurality of through holes 624 within a respectiveROI 602, each of the plurality of through holes extending between aperipheral outer wall and the peripheral inner wall. Each hole extendsbetween a portion of a peripheral outer wall 620 and a portion of aperipheral inner wall 622. Each through hole 624 has a diameter L₁between about 250 micrometer (μm) and 2500 or between about 250 μm and2000 um, between about 300 μm and 1000 um, between about 350 and 500 um,or between about 400 μm and 450 um. No cracking was observed in thelaser drilling of the through holes.

In embodiments, the ceramic workpiece of FIG. 6 may include a nitridebonded silicon carbide material. It is to be understood that theembodiment illustrated in FIG. 6 is only a non-limiting embodiment ofthe current disclosure, and that other ceramic materials may also beused in the ceramic workpiece. Furthermore, other dimension ranges andvarious patterns and complex array of the through holes can also beachieved with the methods of the current disclosure and are within thescope of the current disclosure.

FIG. 7 is a magnified cross-sectional view of a portion of the ceramicarticle of FIG. 6 , showing a through hole 624 and its surroundingstructural details made via the laser drilling as described in FIG. 6 .Each through hole 624 extends between a portion of a peripheral outerwall 620 and a portion of a peripheral inner wall 622 in a direction “L”(similar to the direction “L” of FIGS. 2A, 6 and 8A). Each hole 624 hasa diameter L₁ with a dimension as similarly described in FIG. 6 . Inembodiments as illustrated in FIG. 7 , as the laser energy source isapplied to ROI 602, the portion of the ceramic material within the ROI602 along the path of the laser (direction “L”) is liquified andvaporized, forming through hole 624 within ROI 602, the through hole 624extending laterally (e.g., in direction “L” shown in FIG. 2A) betweenthe peripheral outer wall 620 and the peripheral inner wall 622 (FIG. 6).

During laser drilling, a portion of the ceramic material along aperipheral inner surface 630 of the through hole 624 is heated toliquification, but not vaporized. This material then re-solidifies alongthe course of the through hole 624 (i.e., direction “L”), forming afirst region 632 adjacent and surrounding the through hole 624 that hasa characteristics that is different than a characteristics of theexisting (i.e., second region 634) of the cylindrical portion 618adjacent the first region 632. The characteristics used herein andthroughout the disclosure may include, but not limited to, a density ofthe material, surface roughness, etc. in each respective region. Forexample, in embodiments, a portion of the ceramic material along aperipheral inner surface 630 of the through hole 624 is heated toliquification, but not vaporized, then re-solidifies along the course ofthe through hole 624 (i.e., direction “L”), forming a first region 632adjacent and surrounding the through hole 624 that has a higher materialdensity than that of the existing (i.e., second region 634) of thecylindrical portion 618 adjacent the first region 632. In certainembodiments, the first region 632, which includes the continuousperipheral inner surface 630, has an average width L₂ in a range ofbetween about 30 μm and about 51 μm Differential density between thefirst region 632 and the second region 634 of the cylindrical portion isbeneficial because it increases hardness and produces milder flowcharacteristics as the hot molten glass or hot gas flows through theplurality of through holes 624, as opposed to contact with a jaggedsurface. It is to be understood that the dimension of L₁ and L₂ areprovided only as non-limiting examples. Other ranges of diameters andvarious patterns and complex array of the holes can also be achieved andare within the scope of the current disclosure.

FIG. 8A shows a perspective view of another embodiment of a ceramicarticle, for example, a ceramic spinner; FIG. 8B is a top view of theceramic article of FIG. 8A; FIG. 8C is a cross sectional view of theceramic article along the line A-A of FIG. 8B, according to embodimentsof the disclosure. As illustrated in FIG. 8A, a ceramic article 800includes: a top portion 810 with a first opening 812, the first opening812 having a first diameter D₁ (FIG. 8C); a base portion 814 with asecond opening 816 having a second diameter D₂ smaller than the firstdiameter D₁ (FIG. 8C); and a cylindrical portion 818 extending betweentop portion 810 and base portion 814, the cylindrical portion 818 havinga peripheral outer wall 820, a peripheral inner wall 822, and aplurality of through holes 824 extending between peripheral outer wall820 and peripheral inner wall 822 of cylindrical portion 818. Inembodiments, the top portion 810 extends laterally (e.g., direction“L”). In embodiments, cylindrical portion 818 extends radially betweentop portion 810 and base portion 814 (e.g., direction “R”). Inembodiments, cylindrical portion 818 has a wall thickness T defined byperipheral outer wall 820 and peripheral inner wall 822 (FIG. 8C). Inembodiments, D₁ may be in a range of about 200-400 mm, or about 300-350mm, or about 300-320 mm. D₂ may be in a range of about 50-300 mm, or ina range of about 100-250 mm, or in a range of about 130-210 mm. T may bein a range of 1-20 mm, or in a range of 5-15 mm, or about 7-11 mm. It isto be understood that dimensions of D₁, D₂ and T are provided asnon-limiting examples, and that the embodiments of the currentdisclosure are not limited to the disclosed dimensions. Variousdimensions of the ceramic article are intended to be included within thescope of the present disclosure. Furthermore, the ceramic article of theinstant disclosure may be developed or used for different applications,including, but not limited to, a ceramic spinner for fiber glass woolproduction.

Material Design

Many design parameters, including, but not limited to, physical andthermal properties of the materials need to be considered in developinga non-metal spinner. Furthermore, complex interplay between theparameters add additional challenges to the material design. Rationalesfor the material design in the instant disclosure and results aredetailed below.

Physical Properties

1. Strength

FIG. 9 illustrates a result of a finite element analysis (FEA) thatdetermines the stresses imparted on the ceramic article of FIG. 8A bythe rotational forces. The ceramic article of FIG. 9 may be otherembodiments of ceramic article such as the one illustrated in FIGS.2A-2C. It can be seen that base portion 814 of ceramic article 800generally receives the minimum stress (less than about 400 psi or about3 MPa from rotation and a cylindrical portion 818 that extends betweenbase portion 814 and top portion 810 generally receives the maximumstress (approximately 5000 psi or 34 MPa) from rotation. FIG. 10 showsmore details of the finite element analysis (FEA) results of a portionof the ceramic article of FIG. 9 . As illustrated in FIG. 10 , themaximum stress from rotation symmetrically impacts cylindrical portion818 with approximately 5000 psi (34 MPa), where the cylindrical portion818 extends radially and connects the base portion 814 and a laterallyextending top portion 810 of the ceramic article 800. In certainembodiment, the stress from rotation impacts base portion 814 with below400 psi (or below 3 MPa). In certain embodiments, base portion 814includes a lateral extending base portion 814 a and a sloped baseportion 814 b coupling the laterally extending base portion to theradially extending cylindrical portion. The lateral extending baseportion 814 a may receive a stress of less than 400 psi or less than 3MPa from rotation, and the slope base portion 814 b may receive a stressof up to 1000 psi or 7 MPa from rotation. In embodiment, the stress fromrotation impacts the laterally extending top portion 810 is in a rangeof about 1000 psi-3000 psi (about 7-21 MPa).

The current disclosure hypothesizes that ceramic materials with astrength that is at least 5 folds higher than the maximum stressexpected in the FEA results may be used as a spinner material, in orderto accommodate typical operations as well as any potential mechanicalfatigue that may be induced through thermal cycling as well as from thefluctuating load and rotation of the ceramic article. In embodiments, aceramic material with a modulus of rupture (MOR) in a range of about5000 psi-25,000 psi (about 34-172 MPa) is used. In embodiments, aceramic material with a modulus of rupture (MOR) in excess of about 5000psi or about 34 MPa is used. In embodiments, a ceramic material with amodulus of rupture (MOR) in excess of about 15,000 psi or about 103 MPais used. In embodiments, silicon carbide with a modulus of rupture (MOR)in excess of about 25,000 psi or about 172 MPa is used. The benefits ofthe ceramic materials of the disclosure include high tolerance of amagnitude of the stress, including the thermal, primarily tensilestresses induced through startup and shutdown transient states.

2. Resistivity to Deformation/Erosion

Compared to the conventional metal spinners, the ceramic spinners of thecurrent disclosure have enhanced resistance to deformation and erosion.FIGS. 11A and 11B compare measurements of Stress (σ) vs Strain (ε)Curves of a reference titanium alloy metal material (FIG. 11A) and asilicon carbide material (FIG. 11B) of the instant disclosure, showingchanges in stress as stain applied to the material increases. The pointsmarked as σ_(ys) and σ_(s) in the curves represent the yield strengthpoints of the respective materials. The Young's modulus calculated fortitanium alloy (reference) and the silicon carbide material are 123 GPaand 410 GPa, respectively.

Equation 1 represents a Bitter's Equation for erosion parameter of amaterial:

$\begin{matrix}{{E = {\frac{{mV}_{i}^{2}}{2}\frac{\left( {1 - {\left( {\text{.041} \times 10^{- 12}} \right)H^{\frac{5}{4}}}} \right)}{T}}}{E = {{EROSION}{PARAMETER}}}{m = {{MASS}{OF}{CONSTANT}{PARTICLE}}}{V_{i} = {{INTIAL}{VELOCITY}{OF}{CONTACT}{PARTICLE}}}{H = {{TARGET}{MATERIAL}{HARDNESS}}}{T = {{TARGET}{MATERIAL}{TOUGHNESS}}}} & {{Equation}1}\end{matrix}$

In comparing the erosion parameters of metal and ceramic materials, itis assumed in the current disclosure that the kinetic energy of thecontact particles would be the same for either case.

${Constant} = {{KE}_{impact} = \frac{{mV}_{i}^{2}}{2}}$

A low erosion parameter E correlates to a high resistance to erosion,and in wear applications, the magnitude of E inversely correlates withexpected life. That is, the lower the erosion parameter E, the longer anarticle is able to remain in service. The relationship between hardnessand toughness drive the erosion parameter, with hardness having slightlymore influence over erosion resistance than toughness.

In embodiments, ASTM C704 test is used to quantitatively measure erosionresistance. ASTM C704 test a 90 deg impingement grit blast at a materialsample and then measures the material loss in cubic centimeters. A lowernumber indicates a more erosion resistance material. In embodiments, thematerial of the current disclosure includes a silicon carbide having anASTM C704 test measurement below 3.0 cc, which is significantly lowerthan that of the conventional metal material used in a metal spinner.

FIG. 12 compares parameters for rigidity (Youngs Modulus, GPa) andhardness (MOH) of various materials for a spinner. It can be seen thatthe technical ceramic materials of the instant disclosure ischaracteristically harder, with a far higher elastic modulus than metal(FIG. 12 ). The combination of a high yield point, a high elasticmodulus, and hardness of the materials of the instant disclosure maycollectively contribute to improved performance and processimprovements. In embodiments, the material that makes up the peripheralouter wall and the peripheral inner wall of the cylindrical portion ofthe spinner, where the stress is highest, has a module of rupture (MOR)exceeding 100 MPa, a Mohs hardness exceeding 8, or a Young's Modulusexceeding 250 GPa, or any combinations thereof.

3. Oxidation Resistivity

Molten glass is an extremely aggressive oxidizer, atomically comprisedof 60-70% oxygen. Platinum, the industry standard due to its strengthand relative inertness, completely wets in air or oxygen. Investigationsinto the wetting properties of molten glass on metals and ceramics showthat more easily oxidized metals or alloys are more easily wetted. Theceramic materials of the current disclosure, for example, silicon basedceramic materials, are completely inert to oxidizing environments andsignificantly less prone to wetting. This would offer significantadvantages of reducing the interference of built-up material on theorifice face of the spinner during production and provide yet anotherprocess improvement.

Thermal Properties

1. Resistivity to Thermal Shock

Thermal shock occurs when the temperature gradient across a body of anarticle results in a stress greater than the strength of the material ofthe article. Four parameters influence a material's resistance tothermal shock: its ability to transport heat, its thermal expansion, itsdensity, and its strength. Its ability to transport heat, orconductivity, influences thermal shock through thermal gradient. Moreconductive materials will have a less severe thermal gradient toinsulative materials. A material with low expansion and low density hasa lower thermally induced stress as result of a thermal gradientcompared to a material with high expansion and high density. Finally,strength of a material determines what the maximum stress the materialmay tolerate without experiencing fracture—the mode of thermal shockfailure. FIG. 13 shows a temperature load over time profile of a thermalshock test, where the material of the instant disclosure is quenchedfrom about 1900° F. to about 600° F. and its resultant strength measuredto quantify thermal shock resistance.

2. Thermal Cycling Fatigue

Fatigue is often characterized in terms of mechanical cycling, howeverit likewise occur when a material's strength degrades as a function ofthermal shock cycling. FIG. 14 shows comparison of mechanical strength(MPa) and density (lb/in³) profile of various materials for a spinner.It can be seen that ceramic material, including a nitride bonded siliconcarbide material of the current disclosure, combines high strength witha high resistance to thermal shock, which allows it to retain itsstrength through the thermal cycling experienced in the manufacture ofglass wool.

3. Structural Stability

Materials with the least deformation as a result of temperature providethe most structural stability in manufacturing processes that occur athigh temperatures. FIG. 15 provides comparison of thermal expansion andthermal conductivity of various materials for a spinner. In someembodiments, the ceramic materials of the instant disclosure have athermal expansion in a range of 3-6 micro-meter per meter per degreeCelsius, or a thermal conductivity in a range of 15-75 Watts per meterper degree Celsius, or both. The ceramic materials of the instantdisclosure retain more strength at the same temperature compared to mostmetals, as well as retaining their shapes and structures due to theirrelatively low coefficients of thermal expansion.

FIG. 16 summarizes a comparison of the material specifications matrixbetween the materials of the current disclosure and certain referencemetals.

Embodiments of the current disclosure provide significant improvementsthat include, but not limited to:

1. longer spinner life due to significantly improved erosion resistanceof the ceramic spinners of the current disclosure.

2. increased yield of highest quality product. The superior propertiesof the materials of the current disclosure including, but not limitedto, erosion parameter, oxidation resistivity, mechanical stability athigh temperature, and rigidity all contribute to an increased yield ofthe highest quality product, for example, glass wool, per spinner. Theholes will remain smaller and more uniform to one another for longer,further significantly increasing the lifetime of the spinner.

3. improved structural and thermal stability of ceramic spinners of thecurrent disclosure due to an increased dimensional homogeneity anddecreased thermal expansion compared to metal spinners at the extremetemperature of operation.

4. excellent thermal shock resistance. With the conventional metalspinner, during production, there are regular instances of mechanicalissues that cause sudden shutdowns in the process. When the process ishalted the glass stops being poured in the spinner, all the sources ofheat to the spinner are immediately shut off, and the spinner quicklycools. This transient thermal condition induces stresses within thespinner, which could ultimately lead to thermal shock—a result when thethermal stress exceeds the materials strength, and in brittle materialssuch as certain refractory materials, it could lead to failure. However,due to the high thermal conductivity of the materials of the currentdisclosure, which lends itself to thermal shock resistance, the thermalgradient would result in a far less severe thermal shock compared toother refractory materials or metals. In embodiments, the technicalceramic material selected may withstand thermal shock scenariosrepeatedly during a 1000+ hour expected life span.

5. lower density of the materials of the instant disclosure providesdecreased weight compared to conventional metal materials, which in turnresult in a decreased strain on the overall system, as well as having apositive influence on the resistance to thermal shock.

6. non-wetting, chemically inert.

7. viable manufacturability for sintered ceramic body. Cast ceramic isat its most fragile in its ‘green’ state, when it is a singular castpiece prior to sintering. While the material of the cast piece isstronger after completing the firing or sintering cycle, the geometryrequired for the glass spinner has never been achievable through a purecasting process, as micro-cracking in the demolding process would beinevitable. Furthermore, the thin cross section surrounding the holepattern of a spinner cannot be reliably produced through traditionaldrilling without cracking or chipping the spinner. Through theintroduction of unique machining processes on a sintered ceramicproduct, as described in the current disclosure, a viable method ofmanufacture can be achieved. Traditional abrasive drilling methods incursignificant costs in machining technical ceramic. For example, materialssuch as silicon carbide or nitride bonded silicon carbide requiresspecialized tooling and increased machining time in order to overcomeits high strength and hardness. Furthermore, though the material is farstronger sintered, the thin cross section of the hole pattern cannot bereliably produced through traditional drilling without cracking orchipping the part.

Approximating language, as used herein throughout the specification andclaims, may be applied to modify any quantitative representation thatcould permissibly vary without resulting in a change in the basicfunction to which it is related. Accordingly, a value modified by a termor terms, such as “about,” “approximately” and “substantially,” are notto be limited to the precise value specified. In at least someinstances, the approximating language may correspond to the precision ofan instrument for measuring the value. Here and throughout thespecification and claims, range limitations may be combined and/orinterchanged; such ranges are identified and include all the sub-rangescontained therein unless context or language indicates otherwise.“Approximately,” as applied to a particular value of a range, applies toboth end values and, unless otherwise dependent on the precision of theinstrument measuring the value, may indicate +/−10% of the statedvalue(s).

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present disclosure has been presented for purposes ofillustration and description but is not intended to be exhaustive orlimited to the disclosure in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the disclosure. Theembodiment was chosen and described in order to best explain theprinciples of the disclosure and the practical application and to enableothers of ordinary skill in the art to understand the disclosure forvarious embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. A ceramic article comprising: a top portion witha first opening, the first opening having a first diameter; a baseportion with a second opening, the second opening having a seconddiameter smaller than the first diameter; and a cylindrical portionextending between the top portion and the base portion, the cylindricalportion having a peripheral outer wall, a peripheral inner wall, and aplurality of through holes extending between the peripheral outer walland the peripheral inner wall, wherein the cylindrical portion comprisesa material having a module of rupture (MOR) exceeding 100 Megapascals(MPa), a Mohs hardness exceeding 8, or a Young's Modulus exceeding 250Gigapascals (GPa), or any combinations thereof.
 2. The ceramic articlein claim 1, wherein the cylindrical portion includes a first regionadjacent and surrounding each of the plurality of through holes and asecond region adjacent the first region, wherein the material in thefirst region has a first characteristics, and the material in the secondregion includes a second characteristics that is different than thefirst characteristics.
 3. The ceramic article in claim 2, wherein thematerial in the first region has a higher density than that of thematerial in the second region, thereby providing a higher-density innersurface surrounding each of the plurality of through holes.
 4. Theceramic article in claim 3, wherein the higher-density inner surfacesurrounding each of the plurality of through holes has an average widthof about 50 μm.
 5. The ceramic article in claim 1, wherein the materialhas a thermal conductivity in a range of 15-75 Watts per meter perdegree Celsius, or a thermal expansion in a range of 3-6 micrometer permeter per degree Celsius, or both.
 6. The ceramic article in claim 1,wherein the cylindrical portion extends radially between the top portionand the base portion, and the base portion includes a laterallyextending base portion and a sloped base portion coupling the laterallyextending base portion to the radially extending cylindrical portion. 7.The ceramic article in claim 1, wherein the plurality of through holeshas an average inner diameter range from about 250 μm to about 2.5millimeter (mm).
 8. The ceramic article in claim 1, wherein the materialcomprises a nitride bonded silicon carbide.
 9. The ceramic article inclaim 1, wherein the ceramic article is a glass wool spinner.
 10. Amethod for preparing an article from a cast ceramic workpiece, themethod comprising: sintering the cast ceramic workpiece to form asintered ceramic body, the sintered ceramic body comprising: a topportion with a first opening, the first opening having a first diameter;a base portion with a second opening, the second opening having a seconddiameter smaller than the first diameter; and a cylindrical portionextending between the top portion and the base portion, the cylindricalportion including a peripheral outer wall and a peripheral inner wall,and forming a plurality of through holes extending between theperipheral outer wall and the peripheral inner wall of the cylindricalportion, wherein the cylindrical portion comprises a material having amodule of rupture (MOR) exceeding 100 Megapascals (MPa), a Mohs hardnessexceeding 8, or a Young's Modulus exceeding 250 Gigapascals (GPa), orany combinations thereof.
 11. The method of claim 10, wherein theforming further comprises: determining a region of interests (ROI) inthe sintered ceramic body for forming the plurality of through holes;directing an energy source to the ROI; and forming the plurality ofthrough holes within the ROI, each of the plurality of through holesextending between the peripheral outer wall and the peripheral innerwall of the cylindrical portion of the sintered ceramic body.
 12. Themethod of claim 11, wherein the energy source is an ultrasound energy ora laser.
 13. The method of claim 11, further comprising: liquifying andvaporizing the material within the ROI in forming the plurality ofthrough holes within the ROI; liquifying, without vaporizing, thematerial surrounding each of the plurality of through holes and forminga first region adjacent and surrounding each of the plurality of throughholes; allowing the material in the first region to resolidify; andwherein the material in the first region has a first characteristics,and the material in a second region adjacent the first region has asecond characteristics that is different than the first characteristics.14. The method of claim 13, further comprising forming a higher-densityinner surface of the first region, wherein the higher-density innersurface extends laterally through both the peripheral outer wall and theperipheral inner wall and has a higher material density than that of thesecond region of the cylindrical portion.
 15. The method of claim 14,wherein the higher-density inner surface has an average width of about50 μm.
 16. The method of claim 10, wherein the plurality of throughholes has an average inner diameter in a range of about 250 μm to about2.5 mm.
 17. The method of claim 10, wherein the cast ceramic workpieceis a singular cast ceramic workpiece.
 18. A ceramic spinner comprising:a top portion with a first opening, the first opening having a firstdiameter; a base portion with a second opening, the second openinghaving a second diameter smaller than the first diameter; and acylindrical portion extending between the top portion and the baseportion, the cylindrical portion having a peripheral outer wall, aperipheral inner wall, and a plurality of through holes extendingbetween the peripheral outer wall and the peripheral inner wall, whereinthe cylindrical portion further includes a first region adjacent andsurrounding each of the plurality of holes and a second region adjacentthe first region, and wherein a material in the first region has a firstcharacteristics, and a material in the second region has a secondcharacteristics that is different than the first characteristics. 19.The ceramic spinner of claim 18, wherein the peripheral outer wall andthe peripheral inner wall includes a material having a module of rupture(MOR) exceeding 100 MPa, a Mohs hardness exceeding 8, or a Young'sModulus exceeding 250 GPa, or any combinations thereof.
 20. The ceramicspinner of claim 18, wherein the material having the firstcharacteristics has a higher density than that of the material havingthe second characteristics, thereby providing a higher-density innersurface surrounding each of the plurality of through holes.